Add support for oauth2 authentication module.

In so doing, extract auth0- and anonymous- -authenticationModule implementations from index.tsx and App.tsx, moving each to it own useXyz hook.

package.json

@@ -36,6 +36,8 @@
       "html-to-text": "^9.0.5",
       "http-proxy-middleware": "2.0.6",
       "jwt-decode": "3.1.2",
+      "oidc-client-ts": "2.4.1",
+      "react-oidc-context": "2.3.1",
       "rapidoc": "9.3.4",
       "react": "18.0.0",
       "react-ace": "10.1.0",